How to Fix a Wheel Speed Sensor on a 2000 Oldsmobile Alero

Your 2000 Oldsmobile Alero has a four-wheel anti-lock brake system that helps to prevent the vehicle from sliding on slick surfaces. The ABS system uses a speed sensor at each wheel to relay its speed to the computer. When the computer detects a difference in wheel speed during braking, the brakes are then pulsed to help prevent the wheels from locking up. The wheel speed sensors are built into each wheel's hubs, so if there is a sensor failure at the front or rear wheels, the hub assembly for that wheel will need to be replaced.

Instructions

Front Hub Replacement

1

Park the vehicle on a level surface and set the parking brake. Loosen the lug nuts on the wheel to be serviced with a lug wrench. Lift the front of the vehicle into the air with the floor jack and place jack stands under the front sub frame. Lower the floor jack until the vehicle rests securely on the jack stands.

2

Remove the wheel lug nuts, then remove the wheel and tire from the vehicle. Instruct an assistant to sit in the vehicle and apply the brakes. Loosen the axle nut with a 3/4-inch breaker bar and 36 mm socket. Instruct your helper to get out of the car.

3

Remove the bolts securing the caliper and bracket to the steering knuckle with a socket and ratchet. Remove the caliper and caliper bracket from the knuckle and rotor. Hang the caliper and bracket from the front suspension with mechanics wire. Slide the brake rotor off of the wheel hub assembly.

4

Disconnect the wheel speed sensor connector from the vehicle wiring harness. Slide the wheel speed connector off of its retaining bracket. Finish removing the spindle nut with the breaker bar and 36 mm socket. Remove the three hub retaining bolts with the socket and ratchet.

5

Thread the hub bolts back into the knuckle and hub at least three full turns and tap the bolt heads in a circular pattern with a hammer to help push the hub from the knuckle. Remove the bolts, then remove the hub from the steering knuckle.

Front Wheel Hub Installation

6

Set the wheel hub into the steering knuckle while guiding the axle shaft splines into the wheel hub. Line up the mounting holes and install the new hub bolts. Tighten the hub bolts to 70 foot-pounds with a torque wrench. Install the new axle nut hand tight.

7

Slide the brake rotor over the new hub; be careful not to drag the rotor over the wheel studs. Support the brake caliper by hand and remove the mechanics wire. Slide the caliper and bracket over the rotor and line up the bracket with the mounting holes in the knuckle. Install the caliper bracket bolts and tighten to 133 foot-pounds.

8

Connect the wheel speed sensor pigtail to the vehicle wiring harness. Slide the wheel speed connector onto its mounting bracket. Instruct a helper to sit in the vehicle and apply the brakes. Tighten the axle nut to 173 foot-pounds.

9

Place the wheel and tire onto the vehicle and install the lug nuts hand tight. Lift the front of the vehicle off of the jack stands with the floor jack. Remove the jack stands and lower the vehicle to the ground. Tighten the lug nuts to 100 foot-pounds.

Rear Hub Replacement with Disc Brakes

10

Place the wheel chocks around the front wheels. Loosen the rear lug nuts on the wheel to be serviced with the lug wrench. Lift the rear of the vehicle into the air with a floor jack and place jack stands under the rear suspension. Lower the vehicle until it rests securely on the jack stands.

11

Remove the lug nuts from the wheel to be serviced and remove the wheel and tire from the vehicle. Remove the caliper bracket bolts with a socket and ratchet. Slide the caliper and bracket off of the brake rotor and knuckle. Hang the caliper and bracket from the rear suspension with mechanics wire.

12

Remove the brake rotor from the wheel hub. Remove the clamp holding the barking brake cable to the brake level with pliers. Pull the cable towards the rear of the car and remove it from the brake lever. Disconnect the wheel speed sensor pigtail from the vehicle wiring harness.

13

Remove the four wheel hub mounting bolts with a socket and ratchet. Remove the wheel hub from the rear knuckle. Remove the backing plate bolts from the rear of the hub assembly and remove the backing plate from the hub.

14

Install the backing plate to the new wheel hub and install the mounting bolts; tighten to 90 inch-pounds. Set the wheel hub into the rear knuckle and install the mounting bolts. Tighten the wheel hub bolts to 70 foot-pounds. Plug the wheel speed sensor pigtail into the vehicle wiring harness.

15

Slide the end of the parking brake cable over the brake lever and set it down into the opening at the rear of the lever. Slide the retaining clip into place over the lever and brake cable. Slide the rotor onto the new wheel hub, being careful not to drag the rotor over the new studs.

16

Support the rear caliper by hand and remove the mechanics wire. Slide the caliper and bracket into position over the rotor and knuckle. Install the caliper bracket mounting bolts and tighten to 85 foot-pounds. Set the wheel and tire onto the vehicle and install the lug nuts hand tight.

17

Lift the rear of the vehicle off of the jack stands with the floor jack. Remove the jack stands from under the vehicle and lower the vehicle to the ground. Tighten the lug nuts to 100 foot-pounds.

Rear Wheel Hub Replacement with Drum Brakes

18

Place the wheel chocks around the front wheels. Loosen the rear lug nuts on the wheel to be serviced with a lug wrench. Lift the rear of the vehicle into the air with a floor jack and place jack stands under the rear suspension. Lower the vehicle until it rests securely on the jack stands.

19

Remove the lug nuts, and then remove the wheel and tire from the vehicle. Firmly grasp the brake drum and slide it away from the brake assembly. If the drum will not easily slide away, tap the front of the drum with a rubber mallet. Set the brake drum aside.

20

Disconnect the wheel speed sensor pigtail from the vehicle wiring harness. Remove each wheel hub bolt one at a time through the access hole in the wheel hub. Remove the wheel hub from the backing plate.

21

Set the new wheel hub against brake backing plate and loosely install each mounting bolt through access hole in the hub assembly. Tighten the mounting bolts to 70 foot-pounds through the access hole with a torque wrench.

22

Connect the wheel speed sensor pigtail to the vehicle wiring harness. Slide the brake drum onto the new wheel hub, being careful not to drag the drum across the wheel studs. Set the wheel and tire onto the vehicle and install the lug nuts hand tight.

23

Lift the rear of the vehicle off of the jack stands. Remove the jack stands from under the vehicle and lower the vehicle to the ground. Tighten the rear lug nuts to 100 foot-pounds.